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Biomass

Within the energy sector, the term biomass refers to all organic matter  that can be converted to energy.

They can be utilised directly (wood fuel), or subsequent to the organic waste methanisation process (biogas) or through a thermochemical transormation process (biofuel).

Renewable energy is energy that is exploitable by Humans, in a manner such that the feedstock reserves are non exhaustable. In short, its speed of growth must be faster than the time required to consume the resource.

The renewable character of energy is dictated by the speed at which the resource regenerates, as well as the speed at which it is consumed.

Oil, including all fossil fuels, are not renewable energy resources; consumed at a rate well above the speed with which these resources are naturally created

WARNING: Biomass,
when misused, is an energy that can be chemically polluting!

 

From where does biomass originate?

Source: Natural Resources Canada

http://www.nrcan-rncan.gc.ca

Biomass is produced by living organisms and is usually produced by the photosynthetic activity of plants. Some of the biomass also comes from animals, insects, micro-organisms, etc.. Biomass is essentially solid, but it may also be liquid. It usually consists of a complex polymer of carbon, hydrogen and oxygen and small amounts of nitrogen and inorganic elements. It often contains trace amounts of sulfur.

We label Biomass the ensemble of organic materials, mainly of vegetable origin, natural or cultivated, land or sea, the result of the solar energy chlorophyle conversion process; with the exception of fossil fuels.

 (The text that follows is from the source: Portal Thermoptim.org)

Biomass is mainly composed of lignin (C40H44O6) (25%), and carbohydrates Cn (H2O) m (cellulose and hemicellulose C6H10O5) (75%). 

 

Thermodynamically speaking, the key parameters influencing biomass combustion are:

  • fuel composition
  • fuel moisture, which determines the enthalpy required to dry the fuel and influences gas composition; as well as influencing the dissociation of CO
  • finally, the solidification temperature and the rate of dissociation of CO2

 

The composition of biomass varies widely depending on its origin and its moisture. It may however retain values close to 25% lignin (C40H44O6) and 75% carbohydrates Cn (H2O) m (cellulose and hemicellulose C6H10O5).

 

Average values for:

Wood Pellets
PCI: 4.4 to 4.6 kWh / kg
Moisture on gross 5-10%
Density: 700-750 kg/m3

Platelets
PCI: 3.3 to 3.9 kWh / kg
Moisture on gross 20-30%
Density: 200-300 kg/m3

Bark
PCI: 1.6 to 2.8 kWh / kg
Moisture on gross 40-60%
Density: 250-500 kg/m3


Examples of biomass:

Forest residues

  • The pulp mill residues such as detergents, tall oil, sludge, bark, and very small nodes.
  • The residues of the secondary wood industry such as sawdust, shavings, shavings, sawdust and sanding waste.
  • The sawmill residues such as sawdust, bark, scrap, yard debris, platelets, and shavings. 

Agricultural residues

  • The manure and bedding of cattle, pigs, sheep and poultry. 
  • Crop residues such as straw and corn stover
  • Waste handling of grains such as chaff, the wheat and small grains of lower quality

Food processing wastes

  • The cheese whey, waste from canneries, fruit pits, apple pomace and coffee

Residues from Municipal Waste

  • Paper, cardbord,rubber, leather, natural textiles, woods, bushes, grass clippings, kitchen water and sewage sludge